Google Slides has a number of pre-set diagrams you can create and modify to match your requirements - including grids, hierarchies for organisation charts, timelines and cycles.
To add a diagram to a slide:
Click on the Insert menu and choose Diagram
Choose the type of diagram you wish to insert
Choose the number of items you want to show in the diagram - this could be steps in a process diagram, dates in a timeline, etc.
Click on the diagram you wish to insert
Click on any part of the diagram to change the text or format.